Color television system



O ct. 21, 1952 R. H. RINES 2,615,087

COLOR TELEVISION SYSTEM Layer.

Oct. 21, 1952 R H, R|NE$ 2,615,987

COLOR TELEVISION SYSTEM Filed April 17, 1944 2 SHEETS-r-SHEET 2ncron/lz//y Films.

Patented Cet. 21, 1.952

COLGR TELEVISION SYSTEM Robert Harvey Rines, Brookline, Mass.

Application April 17, 1944, Serial No. 531,451

31 claims. 1

The present invention. relates to electric systems, and moreparticularly to television-receiving `systems that, while having moregeneral elds of usefulness, are especially adapted for use in colortelevision.

In the prior art, color television has been accomplished by allowing acolor disc to rotate in iront of the iconoscope or other common type oftelevision-transmitting Itube. The optical field produced on theiconoscope mosaic has been scanned -by the elec-tron stream of theiconoscope While each color disc was in front of the tube. A Similardisc, at the receiving station, has been synchronized with the disc atthe transmitter so that; as the electron stream of thedisplay-cathode-ray tube at the receiver reproduced the iields scannedat the transmitter, the appropriate color disc Was in front of thereceiver-oscilloscope. The successive color scans occurred at such arate of speed that they appeared as a, single image in its true colors.

An object of this invention is to provide a new and improvedcolor-television-receiving system.

A further object is to provide a novel colortelevision system that shalleliminate the need for bulky moving parts, such as color lters.

A further object is to provide a complete colorimage-producing systemcontained in a cathoderay tube, with no external parts other than thesynchronizing and impulse circuitry associated with the receivingsystem.

It has been proposed to print lines or strips of diierently coloredluminescent material on a screen, thereby forming a mosaic of interlacedluminescent strips positioned inside the` cathoderay tube. This processcalls for coating the luminescent material on a supporting screen. Theinherent overlapping of the luminescent material, coated as thusproposed, and the sympathetic luminescence of adjacent strip coatingsrender these proposals disadvantageous.

It has also been proposed to provide a series of sets of metal stripscoated with luminescent material and electrically charged in synchronismwith the transmitter color disc to cause the scan oi a particular set ofstrips. Such a construction and scanning procedure is intricate andcomplicated.

A further object of the present invention, therefore, is to overcomethese complexities by using a new and simple type of mosaic, ruled toprovide a grating, the rulings of which are filled with luminescentmaterial. As Will be later pointedout, such a system permits the screento be actually lthe cathode-ray-tube face itself, thus 2, lending itselfto present manufacturing method-s, insures against sympatheticluminescence of adjacent rulings, and adapts itself to extremely simplescanning procedures.

Still a further object is to provide simple methods of making thesegrated mosaics.

Other and further objects will be explained hereinafter, and will beparticularly set forth in y the appended claims.

The invention will now be more fully explained in connection with theaccompanying drawings, in which Fig. 1 is a diagrammatic view ofcircuits and apparatus embodying the invention as incorporated in acommon color-television-receving system; Figs. 2 to l0 representexplanatory diagrams and Wave forms; and Fig. l1 is a view of acathode-ray-tube screen illustrating a feature of the present invention.

An antenna 22 receiving the radio-frequency transmission from A'asending station (not shown) feeds a radio-frequency amplier 24 which, inturn, feeds into'a detector28 that is superheterodyned by a localoscillator 26. Part of the output of the detector 28 is fed to thevideo-frequency amplifier 30 which controls the voltage between thecathode 5 and the vcontrol grid 'l of the display cathode-rayoscilloscope 42. Thus, electrons emitted from the cathode 5, in responseto the energizing of the control grid 1, will pass in quantitiesdependent upon the signal strength transmitted during a particular scanof the iconoscope mosaic at the transmitter. The Adetector 28 also feedsa synchronizing signal-separator 2l i that separates out the triggeringpulses for the horizontal-sweep circuit Il, the vertical-sweep circuitI9, the backstroke blanking circuit 35, and the motor 32, which, in mostcolor-television circuits, is used to revolve a color lter. The hori-Zontal-sweep circuit feeds the deflector coils i3, 23 and producesperiodically the line-scan, while the vertical-sweep circuit i9periodically energizes the coils I5 and 25 to eiiect the fieldscan. Allthis is according to well-known television techniques.

The screen face All of the cathode-ray tube 42 is of uniqueconstruction. It involves the providing of depressions in the face ofthe screen within the cathode-ray tube for holding the phosphorescentluminescent material. Among the advantages of such a construction arethe obviating of overlapping and consequent edgeluminescingeiectsbetween adjacent portions of apattern of luminescent material on thescreen, since the luminescent material is confined to the depressions;the resulting clarity and sharpness of luminescent indication providedby the electron stream impinging upon the luminescent material conned tothe depression; the rendering more diicult the dislodging andburning-off of the luminescent material by the electron stream; and theadaptability for accurate mass-production of particularluminescent-material patterns as a result of the use of easilyreproducible depressions. While this feature of the presentinvention,p-therefore, is of general use for cathoderay-tube screensandthe like wherever the above advantages and others are sought, it isparticu-v larly adapted for use in the above-described illustration ofcolor television.

Thus, in Fig. 1, for the color-television use, a pattern of depressionsis provided inl the. cathoderay-tube screen 40 that constitutes `agrating,y

ruled in the face itself, with successive substantially equally spacedlines of the grating fllle'di with various types of .phosphore The depthof the grating-'or ,gr-.ooved area ,may be :about 0.002 millimeter. TheWidthofeachmuling, however, should preferably be -justslightlylargerthanthe Width of the electron ,streamin-the ,'cathodefray tube @42 in'orderfthat, among othenreasons, :the degree of eaccuracy requiredof -the hereinafter described biasing and .scanning system-be ,-'not toogreat. Thefanodes vand II may be'zadiusted to produce an extremelynefstreamfaboutonefourth the width ofthel customary,televisionelectronstream. If' every four gratings lfrom-the top, such as y2, 8, I4,20,-etc., are filled with, say;zinc orthosili,cate,.then,a greenphosphorescent Vscreen has :been lcreated,.andanfelectron-streamstriking any .layer 2, r8, I 4, 20, etc.,1Will.,produce:affgreen coloron the scope face 40. similarlyzgratings 4,I0, I6, etc., might be ,fllled'orfembedded with zinc oxide so thatan=electron ystream vstriking anyof vthese layers would produce :aeblueluminescence on thescope face. Anda redoryellow or any desired colorlphosphorimay `ocqupy'the remaining-set ofrulings -6, I2, I8,wetc;;for---example, vzinc beryllium silicate.V

A plurality of like sets of areas including a first area -2, 4,-B` and alast area, .not shown, .are thus provided on the screen 40 ron which theelectron stream impinges, -each set having, a plurality of likesub-areas or layersallextendingin the same direction, :which maybeassumed-,to be horizontal. Theflrstvset-.of areas y,is'cprov-ided withlthe-successively disposed-sub-areasfor layers 2, `I and 6 equallyspaced ialong-,a ,direction perpendicular to the first-named direction,Which-may :therefore be ..Vertical-.. The ysecond .set of `areasisprovidedfwith Asuccessively disposed sub-areas .or .layers I8, I .andI 2,1 similarlyV equally spaced vertically. The thirdsetfofareas;is.;provided with successively disposed :sub-.areas or layers I4,IB, and I 8. also `equally spacedvertically. The .fourth set ;of Aareasis r.provided- With successivelydisposed sub-:areasnr layers v2i), etc.,vlike,- wiseequally,.spac.ed vertically, andso on. The sub-.areasnrlayers- 2.13, I4, 20etc..of .the setsof areas are similar,correspondingtogreen. They are substantially .equally spaced Aalongthe.vertical direction between the-rst-.greenlayer 2 `in the rst `area2,14, 6 and alast.greenlayerA in the last-area,fnotshown; The sub-areasorlayers 4, I0, I 6, etc., ofc'the'sets of. areas are .alsosimilan butcorresponding to blue. "They arelikewise equally spaced 'verticallybetween the iirst lblue layerdinth'ers't area 2, 4,16 and a 'lastbluelayerfiny the last'area, not-shown; 'The sub-.areas orlayers 6, I2, I8,etc., ofthe'setsof ,areas are lkewisesimilar, butcorresponding-to red;`'I'he red layers are also equally spaced vertically between the iirstred layer 6 in the first area 2, 4, 6 and a last red layer in the lastarea, not shown. The sub-areas or layers of each area are thus coloredin sequence to correspond to the sequence of colors of the lter at thetransmitter.

Three sets of gratings have been provided, and an electron streamhitting any set Will give luminescence of a color depending on the typeof phosphor in that set. The three primary colors may easily Abe used asmentioned above, so that the set 2, 8, I4, 20, etc., gives greenluminescence,

the set 4, Il), I6, etc., blue; and the set 6, I2, I8, -et c red.

Each groove or ruling is separated from its yadjacent1ru`lings by thenon-phosphor material .'ID `of,theiaQeJIILf Since the luminescentmaterial is embedded in the grooves of the face 40, the non-luminescentmaterial I0 is in the same plane as the top of the luminescent materialso that the facematerial 'I0 effectively prevents sympatheticlluminescence of adjacent grooves.

It is desired-to .cause-the electron stream'to successively -scanzeachfset oflrulings.V For exam.- ple, the stream will scan theruling,2then.1he ruling 8, then ftherulingll thenthe-rulingq20, etc.,until all the layers of thisgreensetfhave been scanned. Thenit,is.desired to causethe electron streamlto scan :ruling `4,thenruling. .l0, then ruling4 11H5,v etc., untilthe second or blue sethasv been scanned. Thestream shouldthen. .start scanning 1ayer,6,.thenI2, then I8, etc., until vthe third or redsethas .beenscanned At suchatime, it is desired to .-startall over-With'the firstor green. ,seta

If -We :assume ,that ther eis,sufficient Vvoltage inithe zverticaLdeector coils` I.5,; 25 to causethe electronustreamto impinge on thelayer `2, and that ,thehorizontal-sweep circuit quickly -scans the layer,2,.then it isonlyvnecessary =that, at ,the end of this scan, theelectron stream..b.e fblanked outuntil such atimeas the vertical-,sweepvoltage would besulicientto ,cause the stream to impinge onthe ylayer 8,thenextl layer l,of the same phosphor. If thisvis repeated throughoutthe- Whole of onescanning process, then We-could accomplisha completescan` of one phosphor-grating.

To make this so, all thatisneeded is to adjust the time constantsoftherecovery circuit of the periodic horizontalvsweep circuit I'I, tosuch-a, value that, in the corresponding period of time, thevertical-sweeppircuit ,shall have .produced a sufficient-voltagechangeto cause the next horizontalscanto Aoccur atthe -properlever ofopera? tionen ,thescopefface onthe next similar phosphor layer.

In,Eig.,2, thesynchronizing pulses that triggertheLhorizontalfsweepicircuit I'I are shown. Fig.- 4 shows y'the,charging kand discharging sweeps of the .'horizontalfsweep `circuitI'I. Assumethat the scan=of ,anyVJayerby the electron-stream takes placeduring the-discharge period'shown as -.-C1R2, -and Athat* thelback-stroke, or recovery, of thestream-occurs during vC1131. Fig.'3.:Shov1s the `negative pulses :applied to :the .Y grid 'I of thecathodeeray tube during this recovery kperiod CiR1,.-.;s.o that during:such period no .electrons reach the scope face 40. In Fig. 5, it isshown that :during this period CiRi, the vertical-sweep circuit IShasbuilt up voltage increments shown as V1,"-V2 -and V3 whicharesufflciently large'to cause -the -next horizontal 'scan- CiRz tooccurgon thefproper layer.l Thus,asshown in ,Fig. 6,'y theiirstscanitakes place on layer 2, thenext on layer 8, the following onlayer |4,. layer 20, etc.

IThus the condition of scanning only one complete set of similarphosphor layers 2, 8, I4, 20, etc., has been accomplished, and,say, agreen image is produced on the screen 49.

' It remains to produce a means of causing the next set of blue phosphorlayers 4, I0, I6, etc., to be scanned during the following Verticalsweep. In accordance with the present invention, the electron beam orstream is b-iased by pre-set biasing voltages applied at the time of theinitiation of the next vertical sweep voltage and hence prior to thecommencement of the next vertical sweep, thereby to insure that thestream will commence the next vertical scanning with the top color layerof the next colorin this case, the top blue layer 4. While the saidbiasing may obviously be effected in well-known ways, the drawingsillustrate a convenient technique in accordance with which the verticalsweep is caused to produce an initial voltage at the commencement of thenext vertical sweep that will start the first horizontal sweep on layer4 instead of layer 2. Then the set corresponding to layer 4, or the bluegrating, will be scanned. This is accomplished by a switching mechanism50, as follows.

The motor 32, which is commonly used to drive a color disc, identicalwith that at the transmitter, can drive a switch 50 which successivelyconnects with contactors 53, 52 and 5|, at the time the red, blue andgreen iilters are respectively in front of the transmitter iconoscope topresent these respective colors in sequence to the transmitter.Contactors 5l, 52 and 53 allow diierent biasing voltages, as produced bybatteries |5l, |52 and 53, respectively, to be applied to theelectron-stream position-biasing device, in this case, to the verticaldeflection coils 5, 25 to produce the proper color selection on thedisplay tube. The voltage values of the biasing batteries |5|, |52 and|53 increase in sequence to correspond to the spacing between the firstlayer and the other layers of each area. The increase in voltage of thebattery |52 over that of the battery thus corresponds to the spacingbetween the layers 2 and A, 8 and le, I4 and I6, and so 0n, and theincrease in voltage of the battery |53 over that of the battery |5|corresponds to the spacing between the layers 2 and 6, 8 and I2, I4 andi8, and so on. if it be assumed that the top grating 2 is a greenphosphor, and every fourth grating is identical, then, while contactor50 makes with contacter 5|, the green filter disc at the transmitter isscanning the iconcscope. The vertical-sweep voltage will feed throughthe slip ring60 and contactor 50 and contactor 5| and biasing battery|5|, to the vertical deection coils l5, 25, and will cause the electronstream in the cathode-ray tube 42 to scan each green ruling aspreviously described. Thus a picture of the .televised object viewed bythe iconoscope through a green filter appears as a green image on thereceiver cathode-ray tube 42 on the grating of green phosphor.Definition will be good particularly if the width of the iconoscopeelectron stream is at least three to four times the width of the veryiine stream preferable in the receiver, This restriction is ratheressential since the intensity gradations produced in the scanning of theiconoscope are reproduced at the receiver on a screen, only selectedparts of which will" produce luminescence during any particular scan.

6' After the greenV phosphor has been scanned and an image producedcorresponding Ato the green object televised bythe iconoscope, the

color filter at the transmitter revolves so that, say, the blue filternext comes into play. Switch 5B, by virtue of its synchronization withthe transmitter color disc, then makes contact with the contactor 52,which causes a greater biasing voltage from the battery |52,corresponding to the separation or lspacing between a` blue and greenlayer, to be applied to the vertical deflection coils I5, 25. The firsthorizontal scan will therefore not take place along' the layer 2, aspreviously, but, due to the additional bias voltage from the battery|52, will take place along the layer 4, the rst blue layer. Thus will ascan of the blue phosphor be produced. If distance'd/3 represents theseparation or spacing of the greenV from the blue rulings, then thebiasing battery |52 must produce a corresponding bias voltage that willdeect the stream ,a vertical distance d/3.

Similarly, when the red color disc is scanning the transmitter,contactor 53 at the receiver will cause the battery |53 to producesuiiicient bias so that the nrst horizontal scan takes place on thelayer E, the rst of the red phosphors.

Itis well known. that color has a diffusing en'ect upon the human eye,so that fewer scanning lines may be usually needed to produce a gooddenition color image than to produce a corresponding black and whiteimage. This means that there can be wider separations between successivehorizontal scans in producing a color` image. The distance d betweensuccessive similar phosphor layers should be so arranged, accordingly,that this diiusing eiect produces a complete and well-defined image onthe color` phosphor gratings.

Fig. I illustrates the synchronizing lpulses triggering thevertical-sweep circuit I9, once to each scan of the iconoscopetransmitter. Fig. 8 shows the position of the color filter at thetransmitter during such scans. Fig. 9 shows how contactors 5|, 52 and 53put in enough additional voltage during respective scans at the receivercathoderay tube 42 to cause the scans to occur first of the greenlayers, then of the blue, and then of the red.

The bias voltage represented by a in Fig. 9 is produced by battery |52and is sufficient to cause the new set of horizontal scans to occur adisplacement d/3 below the rst level of operation' on the layer 2; i.e., on layer 4. Similarly, the voltage b shows the additional d/3 biasvoltage put on by the battery 53, to cause ascan initiating with the topred phosphor 6. The switch. 50. in between successive connections to thecontactors 5l, 52 and 53, during the back-stroke or discharges of thevertical-sweep. voltage, as illustrated in Fig. 9, disconnects thevertical-sweep circuit Ill from the vertical deiiection coils'|5, 25,thereby providing convenient backstroke blanking. Fig. 10 shows thecolor phosphor scanning sequence.

The observer thus sees three successive di'erent-colored images,slightly displaced from one another. If this displacement is smallenough,

and it can be made so by using fine gratings and by adjusting the anodesIl and 9 to produce an extremely ne electron stream to fill thegratings, the observer will not be able to detect the slightdisplacement of the three scans, and will see but one image in its truecolors.

A simple method of constructing the novel 7. cathndeeray-:tube screens"tofx'thie :present inventionA Willinowtb'erdescribed, fappliedtofthecome plete .oscilloscope grating illustration. .Rule-.ian independentgrating. .onieachzof threey thin transparentrsheets. 44, 46,"48,;suchVaszne glass. Supe pose the Vseparations'of Y'the ruling is d. VMoisteneach* sheet, Aand :then dry off the sheet. The rulings will .remaindamp. The application .of a powdered :phosphor Lto thesheet, andthesubsequent dustingzoi offthexsheet,` will leavethe grat# ings '.full'zofphosphor. These same moistening, drying rand.luminescent+material411llingsteps,v of

course, are equally applicable to .other types of.

depression patterns,ttoo. Thus,1in the above illustration, threeseparaterphosphor gratings have been .fmade Eachsheet, ofcourse, is auseful cathode-.ray-Qtube screen. Where itis desired to obtainatcomposite assembly "of interlaced' screens, a'szfor'rmultiacolorfpurposes,;it:merely remains yto position thelsheetsfso-as tostaggercthe gratings so tha'tta completeinterlaced three-color gratingis produced. If the top grating of the second thintsheetzbe'iplaceda'adistance d/S fromthetop gratingfof i the rst sheet, .2 and the ,topgrating :of thevthirdf sheet is `placedzd/l4 belown the top grating of'the second e sheet, athen gratings :two and one, andl :three fand two,.`respectively, can be joined,;if "'desired, at 'the "outer `edgesfwithglass cement, producing :a .three-'color grating.

Further vimodiiicationsf-will occur 'to 'persons skilledingthe,-artfand'all :such are considered to fall"-.Within"the:spirit'andscopeiof the invention, as y:denediin the `appended claims.

1.;A transparent tscreen ".forfiincorporation at theffrontof aicathode-ray-itube having'ian electron stream-7 the :screen `beingnprovided on its facead'apted' to be disposed' inside `the l tube facingthe electron stream with a plurality of .depressions keach f' containingvluminescent material of fwidth "larger" than `thewidth 'of 'the'electron stream.

2. 'Arno'saicthat 'comprises'several thin'sheets eaciirule .d to provide`a grating,"the^ruling lof each grating 'being filled `withrluminescentA materials,1and"the sheets of vgratings being joinedwiththecrulings of'the respective :sheets staggered "to interlace athem.

3. A cathode-ray tube having a screen provided rwith'a'facedisposedinside 'the tube ruled withf'a series of'grooves to proVide'agrating; the grooves containing multi-:colored luminescing materials,and lmeans'for producing an'electron stream to-'scan the 'materials inorder to cause them to 1uminesce,'the luminescing materialsbeingsdisposed in. scanning paths-'along areas of WidthY .larger "thanthe width .of the electron stream'.

"4. A colore'television*receiver yhayingascreen provided- Witha.plurality of like sets'of areas including aifirst areaand'a'lastareaeach having apluralityof :like layers 4extending a firstldirection constituted fof material that luminesces inr-responseto tthe.actionzithereon o'f van yelectron stream, the luminescent material.ofthe layers uof each areaA luminescing .infcolors in sequence,:similarly luminescing `colorzlayers .of the successively disposedareas: being substantially equally spaced along asecond-directionbetween-a rst similarly luminescing .color :layer .in-the virst Aarea and aflast' similarly luminescng ,color4 layer. yin'the last area, means .for producing an electron stream,

fnrximpnging on the screen, a lplurality* of. voltage sources havingpredetermined -voltage 4fvalues increasing` in/sequencelto correspondto-fthe spacing between the flrst :layer :andthe other layers of eacharea, a first deflection means for deilectd ing the :ele'ctronsstream:periodically to .cause-the electronv stream to;.scan'the' vlayerssuccessively .in the -iirst direction, a f second .pdeiiectioni means,.ga sweep circuitfforproducing .aperiodic sweep voltage, :mea-ns.`connecting 'the'sweep circuitto .the second deflection.meansftoscausethe second-ideilection means,"duringzeach-:sweep of the periodicsweepfvoltagetodeflect thefelectron stream upon the conclusionfofethescanning of each layer from each.scannedzlayeraof.-each color to thenext adjacently disposed layer ofzsimilar luminescing'color-.untilall-.of Jthesmilarlyluminescing color layers Ifromithe firstsaidfsimilarly luminescing color layerfto `sthelast: said similarlyluminescing color layer :ha-Ve :been scanned, and means operable upon'thegcompletion 'of the :scanning .of .the last layers fand-prior ttothewcommencement of each next following-sweep :of thef periodicy sweepvoltageftofaddztheffvoltages;of the l'plurality of voltagev sources in:the .order of their increase in sequence 1to the; periodic sweepvoltage of the sweepcircuitin order to iimpingethe electron stream upon.-the-.nrst-layer of thefcolornextin sequence .tothewsaidpiirstz'similarly luminescin colorylayer.

5. A color-televisionrreceiver having Ia screenprovided.withiafplurality-oflikersets of areas including-airst:areaandia last areaeach having afplurality ofxlikerlayers extendinginafirst directionrconsttutedr of i material thaty luminescesinresponseto the :action vthereon Yof Aan :electron stream; theluminescent-maten' alof the layersnf eachrarea' luminescing inA colors'in sequence,A similarlyffluminescing color :layers of the .successivelydisposed .areas beingvsubstantially equally spaced' alongfasecondidirection-between ai rst similarly luminescing vco1or.'layer vinrthe rst areaand a Blast similarly luminescing color layer'inth'e last'area; means :for producing 'an electron-.streamfor'impingingon.the.screen, a pluralityof voltagetsources Ahavingpredetermined voltage values increasing inisequen'ceto correspond to thespacing between lthe iirst .layer and the other layers of eachfarea, Aarst deflection means lfor delectingsthe electron streamsperiodically tocause the electronfstream"tofscanthe layers successively Yin theiirstdirection, a second deflection means, a sweep circuit .for producing aperiodic sweep voltage, means connecting `the'sweep Acircuit to thesecond deection means to cause vthe second deflectionlmeans,duringeach'sweep of the periodic'sweep' voltage,l to rdelectthe electronstream upon the conclusion of thescanning of each layer from eachScanned'layer of each color tothe next "adjacently f disposed'layer ofsimilar luminescing coloriuntil all? of the similarly 'luminesc-L ingcolor-layers riromthe rst said similarly lumi-l nescing color-layer t0the last said similarly luminescing color layer "have been scanned,means operable upon the completion .of the scanning of thelast layersand prior'to the commencement of .each next following sweepv .oftheperiodic sweep voltage to addthe'voltages .of the plurality ofvoltage sources in theorder of their increase in sequence to the jperiodic sweepvoltage .ofrthe sweepcircuitin order to impinge theelectron. stream .upon the lrstlayer .of the .color next .in sequence.to .the .said Mrst similarly luminescing colorlayer, andmeansfordisconnecting vthe .periodie sweep voltage imm .the .seconddeflection..

means during `the A.period I.between the ,completion of the scanning ofthe last layers and ,--the y 9 commencement of the next following sweepof theperiodic sweep voltage.

6. A color television receiver having a screen provided with a pluralityof like sets of areas including a first area and a last area each havinga plurality of like horizontally-extending layers constituted ofmaterial that luminesces in response to the action thereon of anelectron stream, the luminescent material of the layers of each area`luminescing in colors in sequence, similarly luminescing color layers ofthe successively disposed areas being substantially equally lspacedvertically between a rst similarly luminescing color layer in the firstarea and a last-similarly luminescing color layer in the last area,means for producing an electron stream for impinging on the screen, aplurality of voltage sources having predetermined voltage valuesincreasing in sequence to correspond to the verticalv spacing betweenthe rst layer and the other layers of each area, a first deection meansfor deecting theelectron stream periodically to cause the electronstream successively to scan the layers horizontally, a second deiiectionmeans,

, a vertical-sweep circuit for producing a periodic vertical-sweepvvoltage, means connecting the vertical-sweep circuit to the seconddeflection means to cause the second deflection means, during each sweepof the periodic vertical-sweep voltage, to deflect the electron streamupon the conclusion of each horizontal scan from each scanned layer ofeach color vertically to the next adjacently disposed layer of similarluminescing color until all of the similarly luminescing color layersfrom the first said similarly luminescingv color layer to the'last saidsimilarly luminescing color layer have been scanned, and means operableupon the completion of the scanning of the last layers and prior to thecommencement of each next following sweep of the periodic vertical-sweepvoltage to add the voltages of the plurality of voltage sources in theorder of their increase in sequence to the :periodic verticalsweepvoltage of the vertical-sweep circuit in order to impinge the electronstream upon the first layer of the next color in sequence to the said.first similarly luminescing color layer.v

7. A color television receiving system having, in combination, areceiver having a screen provided with a plurality of like sets ofgrooved areas including a rst area and a last area each having aplurality of like grooves extending in a rst direction and filled withmaterial that luminesces in response to the action thereon of anelectron stream, the luminescent material in the grooves of each arealuminescing in colors in sequence, the grooves containing the similarlyluminescing color luminescent material of the successively disposedareas being substantially equally spaced along a second directionbetween a first groove containing similarly luminescing colorluminescent material in the rst area and a last groove Vcontainingsimilarly luminescing color luminescent material in the last area, meansfor producing an electron stream for impinging on the screen, aplurality of voltage sources having predetermined voltage valuesincreasing in sequence to correspond to the spacing between the firstgroove and the other grooves of each area, a first deection means fordeecting the electron stream periodically to cause the electron streamto scan the grooves successively in the first direction, a seconddeiiection means, a sweep circuit for producing a periodic sweepvoltage, means connecting the sweep t. circuit to the second deflectionmeans to .cause 'the'second deflection means, during each sweep larluminescing color until all of the grooves con-l taining the similarlyluminescing color luminescent material from the first said groovecontaining the similarly luminescing color luminescent material tothelast said groove containing the similarly luminescing color luminescentmaterial have been scanned, and means operable upon the completion ofthe scanning of the last grooves and prior to the commencement of eachnex't following sweep of the periodicsweep voltage to add the voltagesof .the plurality of voltage sources in the order of their increase insequence to the periodic sweep Voltage of the sweep circuit inorder toimpinge the electron stream upon the rst groove containing luminescentmaterial of the color next in sequence to the said first groovecontaining the similarly .luminescing color luminescent material.

vfirst area and a last area each having a plurality of like layersextending in a first direction constituted of material that luminescesin response to the action thereon of an electron stream, the luminescentmaterial of the layers of each area luminescing in colors in sequence,similarly luminescing color layers of the successively disposed areasbeing substantially equally spaced along a second direction between arst similarly lumnescing color layer in the first area and a lastsimilarly luminescing color layer in the last area, means for producingan electron stream for impinging on the screen, a first deection meansfor deecting the electron stream periodically to cause the electronstream to scan the layers successively in the first direction, a seconddeection means, a sweepv circuit for producing a periodic sweep voltage,means connectingithe sweep circuit to the second deflection means tocause the second deflection means, during each sweep of the periodicsweep voltage, iirst to deflect the electron stream upon the conclusionof the scanning of each layer from each scanned layer of each color tothe next adjacently disposed layer of similar luminescing color untilall of the similarly luminescing color layers fromthe first saidsimilarly luminescing color layer to the last said similarly luminescingcolor layer have been scanned, and means operable upon the completion ofthe scanning of the last layers and prior to the commencement of eachnext following periodic sweep voltagefor biasing the position of theelectron stream Ain order to impinge the electron stream upon the firstlayer of the color next in sequence to the said rst similarlyluminescing color layer. l

9. A color television receiving system having, in combination, areceiver havinga screen provided with a plurality of like sets of areasincluding a first area and a last area each having a plurality of likelayers extending in a rst direction consti'- tuted of material thatluminesces in response to the action thereon of an electron stream, theluminescent material of the layers of each area luminescingin colorsin'sequence, similarly luminescing color layers of the successivelydisposed memos? areas bei-ng substantially equally :spaced Yalong. a

' second d-irectionbetween a rsts'imilarlyluminescing .color .layerinVthejIirst :area-.anda last similarly luminescingv color layer inithelast-area, means for producing an L. electron...fstrea1n :for

-impinging on .th-e. screen,V a' plurality ofL 'voltage age,.means.connectingthe-.sweep circuit to the..

second deiiectioni: means' to. .cause the. second deection mea-ns,yduring each sweepuofi `the periodiov 'sweep'voltage,l firstr todeiectf'ftnez 4electron `stream upon theuconclusionz tof the scanningA.of eachlayer from each scanned layerrof. each color to the nextAadjacently. disposed .layer of. similar luminescing .color until all of.the similarlyluminescing color layersfrom the ilrstzsaidl similarlyluminescing color layer "to the last said similarly luminescing colorlayer have been scanned,Y and:

motor-driven-fcontactor Imeans yoperable upon .the completion of fthescanning. vof the-.last layers rand `prior to lthe. commencement of.each next lfollowing sweep of the 'periodicr .sweep voltageto-add the.voltagesl of the. pluralityof voltage .sources in theorder of theirincreasefinqsequence to! the periodic sweep'` voltage of Athe sweepvcircuit in orderrto. impinge .the electron stream upon the iirst layer.ofthe color `next'in .sequence to the saidl first similarly luminescing.color layer.

l0. A system for producinga likeness-oran objectin .the original colorsAof the object having, in. combination, 'means forr receivingsignalscorrespondingzto the object in its primary colors,: a cathode-ray tubehaving a. screen. provided with a pluralityA of like sets ofareasincluding a first area and a. last area each having; a, pluralityof likelayers extending.v in a iirst direction constituted of materialthat. luminesces in .response to themaction thereon-of. an. electronstream, the luminescent .material of the layers. of eachzareaiuminescing in the primary colorsA in `sequence. to correspond to theprimary .colors .of the Aobiect, similarly luminescingv primary-colorllayersof the successively disposed .areasbeingf'substantially .f

equally ispaced along a'. second -direction lbetween a firstsimilarlyluminescing primary-color'layer in the rst area andv a last similarlyluminescing primary-color layerin. the last area, vmeans for producingan electron stream for impinging' on the screen, a plurality of voltage.sources having predetermined voltage values. increasing in sequence tocorrespond to the'spacing between vthe iirst layer andtheV other layersof each area, a iirst deflection means for deflecting the electronstream. periodically. to .cause the electron` stream to scanithe4 layerssuccessivelyin theiirstid'irection, asecond deection means..afsweepicircuit for. producing' a` periodic'sweep voltage,` meansconnecting the sweep circuit to the second deflection means tocausefthe.l second. deflection means, during each sweep .ofthe'periodic-sweep voltage, to deiiect the electronzstream jupon the.conclusion' of the rscanningLof :each'flayer from: each scanned layerof. each primary colorito thel next adjacently disposed: layer of.similar luminescing primary coloryuntil .all of the.simlarlyfluminescing primary color layers from ythe first said similarlyluminescing primary-colorlayerto the. last .said similarly. luminescingprimary-color: .layer .have beenscanned, means fop erable uponithe Acompletion of the scanningof the lastfiayers prior to .the commencement vofeach vnext followingl sweep-of the periodic sweep zvoltage to add thevoltages fofthe. plurality of voltage'-sources in theorderof their.increase in sequence tai-.the periodic ysweepwvoltage of the sweepcircuit-in orderto.'irnpingecthev electron stream uponthe rstlayer of.the primaryrcorlor next in sequence .ton .the `'said iirst :similarlylurninescingl .primarycolor layer., andfmeans .responsive to.thereceiving means for modulating the electron :streanr las it scansu"the :similarly f luminescing. primaryecolor layers with the received.signals .correspondingito :thercorresptm'ding.V primary colors of the'object.

. 11. A;systemsiforproducing al. likeness :oi an object inthe origina-1v.colors ofi the obiect' hav- .iing,tin combinationfm'eans for 'receivingsignals Y corresponding tothe. objectain' its three-primary colors;` a'vcathode-.ray tube havingv av screenrprovided with. a:.plurality. of.`:like fsets :of .areas` inzcluding. a.' rstzareaand a last-area each`having i three like :layers extending in.. aiiirstl directionconstituted;offgmaterial thatY .luininesces 'inLre- .sponseto'....the:.acti\on thereon.. offen-.electron stream,4 1.the-luminescent material.l of the 1 three layers.. of each. area.luminescing inthe primary colors 'inasequencefto :correspond to'thelthree `primary. .colorsA of :the object; similarly luminesc- 1 ing.primary-.color layers ofllthe. successively.' ldisposed areas. being.substantially equally' spaced along' la secondi direction :between` a.nrst :similarly iuminescing:primaryecolorlayerlin.thei iirst area nandaa last: similarly luniinescing primarycolor layer iny.therlastarea;:means: forA producing an, electron `stream forimpin'ging on the screen, three voltage. sourceshaving. predeterminedYvoltage values increasing .in sequence. to `correspond toy they spacingbetween'4 the rst layer Sand the other layers of each; area, aiirstldeiiectionm'eans for deflecting'the electron stream'.`periodically-to cause the electron .stream to scan theflayerssuccessively inthepiirstK direction, ai second;r deflection means, asweepcircnitvforA producing asperiodicrsweep voltage, means .connectingthesweep circuit'to .thesecond deiiection vmeans 'to :cause the seconddeiiectiont means, during. each sweep lofthe periodic sweepvoltagartodeflectthe electron :stream upon .the :conclusion fofthescanning of eachlayer; from each. 'scanned layer; of:l each f primary color f to the.next 1 adjacently: .disposed layer of similar'. primary luminescingl'color' until all aof' the; similarly luminescing primary-color layersfrom the` ,first :saidsimilarly luminescing primary-.colorzlayer to ,the.last'ysaidusimilarly luminescing ,primary-colori layer :have beenscanned, meansroperablei upon `the completion 'of vthe v scanning Aofthe. last :layers: and: prior to )the commencement `ofeach; nextV'following sweepfni .the period-ic.` sweep :voltage to: add ,thevoltages of the three voltage sources. inatheorder of. their .increasein. sequence to .ther periodic Ysweep 'voltage of the' sweep circuit.inorderzto impingeihe electron strearnfV upon the first llayer of .thepri'- m'ary color next in'- sequence to the: said. :first similarlylluminescing primary-color. layer; and means: responsive to. theAreceiving means for modulatingv the electron streamas it scans .thesimilarly luminescing, primary-colorlayers with the receivedsignalscorresponding .to theY corresponding-primary colors of :the object.

12. A methodof constructing; a luminescent screen that.compri'sesfrulingv grooves inthe :face of the screenn toi-provide:agratingtmoistening 'the.rscreen`....dryingz the'. facezof: the screen,and

1113 inserting luminescent material in the moistened grooves of thescreen.

13. A method of constructing a luminescent screen that comprises rulinggrooves in the face of the screen to produce a grating, moistening thescreen, drying the face of the screen, applying powdered luminescentmaterial to the, screen, and dusting the powdered luminescent materialoff the face of the screen in order to leave the moistened grooves ofthe screen containing luminescent material.

14. A method of constructing a luminescent screen that comprises rulingseveral independent gratings on each of several thin transparent sheets,filling the rulings on each sheet with luminescent materials,positioning the sheets to staggerthe gratings and joining the positionedsheets to maintain the gratings staggered.

15. A method of constructing a multi-colored luminescent screen thatcomprises ruling several independent gratings on each of several thinsheets,lling the rulings on each sheet with a particularcolorluminescing material, positioning the sheets to stagger the gratings andjoining the positioned sheets of gratings such that vthe assembly ofjoined sheets shall provide a screen of interlaced multi-colorluminescing rulings.

16. A multi-colored luminescent screen that comprises several thinsheets ruled to provide gratings, the rulings of each sheet being lledwith a particular-color luminescing material, and `the sheets beingjoined with the rulings of the respective sheets staggered such that theassembly of joined sheets shall provide a screen of interlacedmulti-color luminescing rulings.

l?. A color-television receiving system for receiving color-televisionsignals having, in combination, a display-cathode-ray tube having ascreen provided With a face ruled with a series of grooves to provide agrating, the grooves being filled With luminescent materials thatluminesce in various colors in response to the action thereon of anelectron stream, means for producing anwelectron stream for impinging onthe screen, means for defiecting the electron stream in one direction,means for deflecting the electron stream in a second direction at anangle to the said-one direction, and means including a motoriorconnecting successively larger biasing voltages in series circuitwith the last-named deflecting means for energizing the last-nameddelecting means to cause the electron stream successively to scanluminescent materials that luminesce in similar colors.

18. .A system for producing a likeness of `an object in the originalcolors of the object having, in combination, means for receiving signalscorresponding to differently .colored portions of the object, Aacathode-ray tube having a screen provided vvith a face and means forproducing an electron stream impinging on the face, the face beingprovided with a series of grooved areas filled with phosphors thatluminesce in different colors in response to the action thereon of theelectron stream t provide differently colored luminescent areas, meansfor causing the electron stream to scan the face along the luminescentareas, contactor means operated in synchronism with the received signalsfor connecting bias voltages into circuit with the scanning means tocause the electron stream successively to scan luminescent areas thatluminesce in similarcolors, and means controlled in accordanceWiththerespective signals received lby the receiving means for producingon the screen a likeness of the object, the luminescent areas beingcaused to luminesce during the scanning in response to the respectivesignals received by thereceiving means to represent the. colors of thecorresponding portions of the object.

19. A system for producing a likeness of an object in the originalcolors of the object having, in combination, means for receiving signalscorresponding to differently colored portions of the object, acathode-ray tube having a screen provided with a face and means forproducing an electron stream impinging on the'face, the face beingprovided with'a series of grooved areas filled with diierent luminescentmaterials, means for causing the electron stream to scan the face. thediiierent luminescent areas of the face being adapted to respond indifferent colors to the action .of the electron stream, contactor meansoperated in synchronism with the received signals for connecting biasvoltages into circuit with the scanning means to cause the electronstream successively to scan luminescent areas that luniinesce in similarcolors, and means controlled by the signals received by the receivingmeans for producing on the screen a likeness of the object, the responseof different areas of the face to the action of the electron streambeing controlled in accordance with the respective received signals toproduce upon different portions of the likeness'colors corresponding tothe colors of the corresponding portions of the object.. .o

20. A system for producing a likeness of an object in the originalcolors of the object having, in combination, means for receiving signalscorresponding to diilerently colored portions of the object, acathode-ray tube having a screen provided with a face grooved to providea grating and means for producing an electron stream impinging on theface, means for causing the electron stream to scan the face along thegrooved areas, the face being provided with a plurality of like sets ofgrooved areas, each set having a plurality of like sub-areas filled withcolor-responding material, corresponding subareas ofthe faces beingadapted to respond with the same color to the action of the electronstream, contactor means operated in synchronism With the receivedsignals for connecting bias voltages into circuit with the scanningmeans to cause the electron stream successively to scan sub-areas thatrespond with the same color, and means controlled in accordance with thesignals received by the receiving means for producing on the screen alikeness of the object and for modifying the action of the electronstream upon the sub-areas to cause different portions of the likeness tobe colored with the colors of corresponding portions of the object.

2l. A system for producing a likeness of an object in the originalcolors of the object having, in combination, means for receiving signalscorresponding to differently colored portions oi' the objectacathode-ray tube having a screen and means for producing an electronstream impinging on the screen, means for causing the electron stream toscan the screen, the screen having a face ruled to provide a pluralityof like sets of grooved areas, each set having a plurality of likesub-areas iilled with color-responding material, corresponding sub-areasof the screen being adapted to respond with the same color to the actionof the electron stream, the colors corresponding to the respectivesub-areas beingnarranged: in the fsarne sequencein thesets of.' areas,means #including a.` motor-drivennconf.- tactor for 'connecting' bias:voltages intoa circuit with` the' scanning. means; for 'causing-:the:scanL ningfmeans to scan .each corresponding: sub1-area of the sets ofsub-areas. in'sequence, yandLrneans controlledl in-accordancewithzthesignals received by r the` receivingm'eans for.. producing'A upon.4 thesub-eareasv portions: of a1. likeness corresponding to the.-.differentlycolored; portions tof the object andlfor modifying the .action`- of the:electron stream upon thesubfareas 'toxcause the'ssaid portions of .thelikeness to'. be frcoloredlwiththe colors of thecorresponding:portions:of the'-.ol:n1ect'.v

221 A'system for producing; a-likeness'of anfob ject. in .the ioriginalcolors.' of the object having, in rcombination, means for receiving-zsignals t core# responding-to thefobjecttin itsiprimary colors, a

cathode-rayA f display "tube fhavingf a l luminescent screen" andmeansforV producing an .electron stream impingingon theflscreen; means foricau's ing. the electron Astream 'to' scanltheiscreen; the screenvlhaving f a face. ruledlto provide'raaplurality of''like sets of.grooved areas, `eacl'uset.-liavingLra plurality of likeyprimarye'coloreresponsive11subareasiilled with luminescent material.that luminesce f in primary colors; lcor-responding" subareas ofthescreen being adapted'to respondl With the @same pri-marycolonto thefaction" of theelectronstream, the primarycolorsrcorresponding to therespective vsub-areas being arranged Tin the samexsequen'ce ingthesetsrof: areas; means fincluding a motor-driven contactor forconnectingfbias voltages into circuit iwith'the scanningmeans -forcausing .th-e scanningmeans to "scanf each corre; spending sub-area ofthe sets-'of sub-areas lin-'sequence,'means for preventingfthe scanningmeans from .scanning other` sub-areas of the f sets of areas `duringvthe scanning-of .particular ysub-areas of! the sets of areas, andrmeanscontrolled lin-'accordance with the `.signals received byv thereceivingmeans for producingupon thelsub-'area-po1' tions of the screensuperposed likenesses-of cor-- respondingrportions `of the object.-in'theirfdif ferent primary colors.

23. A System .for producing a likeness 'of-fan' object in the originalcolorsof the object having; in combination, means for receivingfsignalscor-v responding -to the object in its Aprimaryfcol'ors, a .cathode-.rayrdisplay `tube rhaving alumiriescent screen. having a. face Iruledrtoprovide agratin`g; therulings'being lled with luminescent material',Aand means for producingan electronfstream-'im' pinging .on the screen,means for 'causing the electron stream to `scan the grating, means'con-'trolled in accordance .with-thefsignals' 'receivedbythe receiving meansandl comprisingfa horizon# tal-sweep-circuit for producing-upon thescreen superposed likenessesi of portions of :the-*object in theirdifferent primary colora-means compris-- ing a. vertical-sweep-circuitkfor causing the producing means to produce superposedlikenessesof theremaining portions ofthe objectr'in` their dife" ferent primary vcolors, i and motor-@driven con` tactor means operatedin synchronifsm-with the received signals for connecting bias-voltagesinto circuitYwith the Vertical-sweep-circuit-td*cause the Aelectronfstrean'i, toIproduce successive' corn--4 plete superposed likenesses of the ob-jectuponthe grating in. their different.` primary .colorsn 24; Avcathode-.ray .tubehaving: Aa `screen :that comprises severalindependent =sets1 of l 'grooves ruled on :each of several'thiniltrans'parent' sheets;l the grooves :on ..each...sheet.;beingrlle'd with luminescent: materials# and.-A the" sheets? being 176joinedflwi-thztheagroovessiofitheerespectiveisheets stagger, and meansfor producingfianieleotron stream.foriimpingingfonith'e screen?.

25.1v A' cathode=rayftube :havingila 'screen--tlt comprises#v several c.independentf setsf of 'f grooves ruled-1. on eachlloflseveral.=thin..sheets,. the iglroov'es on L eachr. sheet being.: filled:witli:..af.particu ia:r.= coloiviiuminescing.:li'imir'rescentfniaterial-`l :and the sheetstbeing joinedfiwithi thegroovesfof the re*-y vspectilv'e:'sheetststaggered 'suchithatthe'fassembiy of joined sheets provides a-'screenfiof-'.interlacedmulti-.l-colorelumines cingigrooves aniflmeans" 'forproducinglanifelectronistreamzzforlr'impingiiigifon the'fscreen.

v26. Aficathode-ray tube-:having afl-screenithat comprises several lindependent' sets-f of'grooves rul'ed'onfreaeh off?severalfthinfsneets,the "grooves on eachifsheetbeingnlledfwith apartieula-colorluminescingzluminescent material yar'iicthe'f sheets bei-ngtijoinedwith". thel groovesflof ''theirespective sheet staggered suchfith'at the:ass'emlily ofi'joined sheets'provides` afscreen of interlaced.multi-color2 luminescing I grooves, means -for 'producingt an electron.streamiiorimp'inging I-'onl the fscrenli and meansifor :causing`thelelectron.. tream? to-scan successively fthe? like-coloredigroovesfor eachiset ofigro'ove's;

27. A color-television receiving systemintcombinationgr.azdisplay-cathoderayf tube havingarscreen.providedliwithffa face7 rledlwitifa; series of-:grooves Vtoipro'viizlealfgratingfthefgroov'es beingf.; lled Withf. luminescent iI materialsthat luminesce in' various colrs* I in yresponseste the actionifthereonoffanfelectron'stream means for producing:an'electronstream-#foriFixripingingfon therscreen',means-forI.rufzriodioallycleii'ecting#the electron.y streaminomet-direction; means for delecting the electron stream .inra-seconddirection at an. angle '.to the. fsaidlone direction', and :means for.connectingsuccessively` larger biasing-'voltage's in` :seriesfcircuit'lwith. the .llastenamed deflecting means.' said: .last-nameddeflecti'ng Imeans being adustedzto `deflect'the.electron-1streaminftlevsaid second' direction during.:y the pericdsfbetween 'suc-l cessivedeiections :Eby the rsthnained dectig means sufficiently 1 to cause .thefelectronf streamA successivelyfto scan luminescent fmaterial thatluminescesfin a sinliilar'z'zolor.`4V

28..' A: system. for :producing Ja- Alikeness `of *an* object'intheoriginal colors @fthe object having'. inlcombination; means-forreceivinglsignals cor# responding toitheobjectl'in its primaryfcolors',1v a acath'odeeray 1 display itubefhaving 'fa "luminescentscreen' havingr a.' .facciA ruled.L to i provide a grating the rulingsof which are 'lledlwith liuninescent materials: that lumin'es'ce l infvarious 'fcolors' in response. to 'the "action" of 'anelectron'f streamland" means :for producing Ian velectron strearn impingfing on .thefscreern:v means I for-causing-.the v'el':',='- tron' stream tosc'an thegratingfmeans'controlled inf accordance 'Withthe"sign`als" `vreceivedbyitl'l'e receiving ='means and kcomprisingj a horizontal'-vsWeep-circuit forperiodically `producingimonline screensuperposecllikeness'es "of" portions '.'of 'the objectv inth'eir different'primaryfcolors means comprising a Verticalsweep-circ'uit for causingtheA producing 'means 'to' produce superposed likenesses ofthe remainingportions of 'the 1objectin'their diierent primary colors, andmeans operated in synchronism with the receivedV signals .for connecting biasvoltages into .circuit with..the-

vertical-'sweep-circuit,` the verticalisweep-circuit.

being "adjusted to deect'the electron'stream verticallyduring theVperiods" between successive'.- -sweepsbyl thehorizontal-sweep:circuitsufncientr 29. A mosaic comprising a plurality of sheets'- each providedwith a set of like layers of luminescent materials, the sheets beingdisposed in parallel planes With the layers of the respective sheetsstaggered to interlace them.

30. A method of constructing a luminescent screen that comprises rulinga grating on each of a plurality of sheets, inserting luminescentmaterials in the rulings on each sheet, and positioning the sheets tostagger the gratings, thereby to interlace them.

31. A multi-colored luminescent screen comprising a plurality of sheetsrespectively provided With sets of like layers comprising respectivelydifferently luminescing color luminescent materials, the diierentlyluminescing color layers of the respective sheets being staggered tointel-lace them.

ROBERT HARVEY RIN'ES.

REFERENCES CITED The following references are of record in the le ofthis patent:

Number 18 UNITED STATES PATENTS Name Date Bilstein Sept. 4, 1923Rudenberg Nov. 14, 1933 Montgomery et al. Aug. 7, 1934 Michelssen Jan.22, 1935 Schlesinger June 8, 1937 Von Ardenne Oct. 26, 1937 Lorenzen May14, 1940 Burnett June 23, 1942 Wilson Sept. 1, 1942 Crosby Sept. 29,1942 Carnaham Nov. 10, 1942 Bedford Jan. 5, 1943 Leverenz Feb. 9, 1943Bamford Mar. 2, 1943 Messner Sept. 28, 1943 Du Mont et al Dec.`28, 1943Russell Jan. 25, 1945 Goldsmith Nov. 13, 1945 Sleeper Nov. 27, 1945Huinagle Nov. 27, 1945 Zworykin Jan. 28, 1947v Kallmann Feb. 18, 1947FOREIGN PATENTS Country Date Number Great Britain Jan. 26, 1939

